Multi-speed transmission

ABSTRACT

The 8-gear transmission comprises an input shaft (AN), an output shaft (AB), four planetary gearsets (RS 1 , RS 2 , RS 3 , RS 4 ), eight rotary shafts ( 1, 2, 3, 4, 5, 6, 7, 8 ), and five shifting elements (A, B, C, D, E). A carrier (ST 4 ) of the fourth gearset (RS 4 ) and the input shaft (AN) are connected to each other as the first shaft ( 1 ). A carrier (ST 4 ) of the fourth gearset (RS 4 ) and the input shaft (AN) are connected to each other as the first shaft ( 1 ). A carrier (ST 3 ) of the third gearset (RS 3 ) and the output shaft (AB) are connected to each other as the second shaft ( 2 ). A sun gear (SO 1 ) of the first gearset (RS 1 ) and a sun gear (SO 4 ) of the fourth gearset (RS 4 ) are permanently connected to each other as the third shaft ( 3 ). A ring gear (HO 1 ) of the first gearset (RS 1 ) forms the fourth shaft ( 4 ). A carrier (ST 2 ) of the second gearset (RS 2 ) and a sun gear (SO 3 ) of the third gearset (RS 3 ) are connected to each other as the fifth shaft ( 5 ). A carrier (ST 1 ) of the first gearset (RS 1 ) and a ring gear (HO 3 ) of the third gearset (RS 3 ) are connected as the sixth shaft ( 6 ). A sun gear (SO 2 ) of the second gearset (RS 2 ) and a ring gear (HO 4 ) of the fourth gearset (RS 4 ) are connected to each other as the seventh gear ( 7 ). A ring gear (HO 2 ) of the second gearset (RS 2 ) forms the eighth shaft ( 8 ). Within the power flow, the first shifting element (A) is arranged between the third shaft ( 3 ) and a housing (GG) of the transmission, the second shifting element (B) is arranged between the fourth shaft ( 4 ) and the housing (GG), the third shifting element (C) is arranged between the first and fifth shafts ( 1, 5 ), the fourth shifting element (D) is arranged either between the second and eighth shafts ( 2, 8 ) or between the sixth and eighth shafts ( 6, 8 ), the fifth shifting element (E) is arranged either between the fifth and seventh shafts ( 5, 7 ), or between the fifth and eighth shafts ( 5, 8 ), or between the seventh and eighth shafts ( 7, 8 ).

The invention concerns a multi-speed transmission planetary design, inparticular an automatic transmission for a motor vehicle, comprising aninput shaft, an output shaft, four planetary gearsets, at least eightrotary shafts, as well as five shifting elements, whose selectiveengagement produces different transmission ratios between input shaftand output shaft, so that eight forward gears and at least one reversegear can be realized.

Automatic transmissions, particularly for motor vehicles, in the stateof the art, include planetary gearsets that are shifted by way offriction or shifting elements, such as clutches and brakes, and astarting element, such as a hydrodynamic torque converter or a fluidclutch, subjected to a slip effect and optionally provided with a lockupclutch.

Within the scope of the Applicant's DE 101 15 983 A1 is described amulti-speed transmission with an input shaft connected to afront-mounted gear train and a rear-mounted gear train connected to anoutput shaft, and a maximum of seven shifting elements, the selectiveshifting of which implements at least seven forward gears without rangeshifts. The front-mounted gear train is composed of a shiftable ornon-shiftable planetary gearset, or a maximum of two non-shiftableplanetary gearsets that are coupled to each other. The rear-mounted geartrain is configured as a two-carrier four-shaft transmission with twoshiftable planetary gearsets and features four free shafts. The firstfree shaft of this two-carrier four-shaft transmission is connected tothe first shifting element, the second free shaft to the second andthird shifting element, the third free shaft to the fourth and fifthshifting element, and the fourth free shaft is connected to the outputshaft. For a multi-speed transmission with a total of six shiftingelements, it is proposed according to the invention to connect the thirdfree shaft or the first free shaft of the rear-mounted gear trainadditionally to a sixth shifting element. For a multi-speed transmissionwith a total of seven shifting elements, it is proposed according to theinvention to connect the third free shaft additionally to a sixthshifting element, and the first free shaft additionally to a seventhshifting element.

Several other multi-speed transmissions are also known from theApplicant's DE 101 15 995 A1, which are provided with four shiftableplanetary gearsets that are coupled to each other and six or sevennon-positive shifting elements, by way of whose selective engagement arotational speed of an input shaft of the transmission can betransferred to an output shaft of the transmission such that nine oreleven forward gears and at least one reverse gear can be engaged.Depending on the gearbox arrangement, two or three shifting elements areengaged in each gear, such that when shifting from one gear into thenext higher or next lower gear in order to avoid group shifts, only oneengaged shifting element is disengaged, and one shifting element thatwas previously disengaged is engaged.

In addition, the unpublished patent application DE 10 2005 002 337.1 ofthe Applicant proposes a multi-speed transmission with an input shaft,an output shaft, four individual planetary gearsets that are coupled toeach other, and five shifting elements, with which eight forward gearscan be shifted into without range shifts, that is, in such a way, thatwhen shifting from a forward gear into the next higher or lower forwardgear, only one of the previously engaged shifting elements is disengagedand only one of the previously disengaged shifting elements is engaged.This multi-speed transmission also features one reverse gear. In allforward gears and in the reverse gear, three shifting elements areengaged at any one time. With regard to the kinematic coupling of thefour planetary gearsets to each other and to the input and outputshafts, it is provided that a carrier of the fourth planetary gearsetand the input shaft are connected to each other and form a first shaftof the transmission; a carrier of the third planetary gearset and theoutput shaft are connected to each other and form a second shaft of thetransmission; a sun gear of the first planetary gearset and a sun gearof the fourth planetary gearset are connected to each other and form athird shaft of the transmission; a ring gear of the first planetarygearset forms a fourth shaft of the transmission; a ring gear of thesecond planetary gearset and a sun gear of the third planetary gearsetare connected to each other and form the fifth shaft of thetransmission; a carrier of the first planetary gearset and a ring gearof the third planetary gearset are connected to each other and form asixth shaft of the transmission; a sun gear of the second planetarygearset and a gear of the fourth planetary gearset are connected to eachother and form a seventh shaft of the transmission; and a carrier of thesecond planetary gearset forms an eighth shaft of the transmission.Regarding the kinematic coupling of the five shifting elements to thefour planetary gearsets and to the input and output shafts, it isprovided that the first shifting element is arranged within the powerflow between the third shaft and a housing of the transmission, thesecond shifting element, between the fourth shaft and the housing of thetransmission, the third shifting element, between the first and fifthshafts, the fourth shifting element either, between the eighth andsecond shaft or between the eighth and sixth shaft, and the fifthshifting element is either between the seventh and fifth shafts, betweenthe seventh and eighth or between the fifth and eighth shaft.

Automatically shiftable motor vehicle transmissions in planetary designhave in general already been described many times in the state of theart and are subjected to constant further development and improvement.These transmission should therefore feature a sufficient number offorward gears, as well as one reverse gear, and transmission ratios thatare very well suited for motor vehicles, with a high total transmissionratio spread, and with favorable progressive ratios. In addition, theyshould enable a high startup gear ratio in forward direction and containa direct gear for use in both passenger cars and commercial vehicles. Inaddition, these transmissions should not have a complicated constructionand should require a small number of shifting elements and avoid doubleshifting within a sequential shifting method so that only one shiftingelement is activated at one time when shifting within defined gearranges.

It is an object of the invention to propose a multi-speed transmissionof the type discussed above with at least eight shiftable forward gears,without range shifting, and at least one reverse gear, in which thelowest possible number of shifting elements is required with the use ofa total of four planetary gearsets. In addition, the transmission shouldfeature a large ratio spread with comparatively harmonic gear stepping,and at least in the main driving gears, a favorable degree ofefficiency, that is, comparatively little drag and gearing loss.

This object is attained by way of a multi-speed transmission having thefeatures of patent claim 1. Additional advantageous embodiments andfurther developments are seen in the dependent.

The multi-speed planetary transmission according to the invention isbased on the type of gearbox diagram of the Applicant's patentapplication DE 10 2005 002 337.1 and features an input shaft, an outputshaft, four planetary gearsets that are coupled to each other, at leasteight rotary shafts, as well as five shifting elements (two brakes andthree clutches), whose selective engagement produces differenttransmission ratios between the input shaft and the output shaft, sothat eight forward gears an one reverse gear are realizable. In eachgear, three of the of the five shifting elements are respectivelyengaged, such that when changing from a forward gear into the nexthigher or lower forward gear, only one of the previously engagedshifting elements is disengaged, and only one of the previouslydisengaged shifting elements is engaged.

According to the invention, it is proposed that:

-   -   a carrier of the fourth planetary gearset and the input shaft        are permanently connected to each other and form the first shaft        of the transmission,    -   a carrier of the third planetary gearset and the output shaft        are permanently connected to each other and form the second        shaft of the transmission,    -   a sun gear of the first planetary gearset and a sun gear of the        fourth planetary gearset are permanently connected to each other        and form the third shaft of the transmission,    -   a ring gear of the first planetary gearset forms the fourth        shaft of the transmission,    -   a carrier of the second planetary gearset and a sun gear of the        third planetary gearset are permanently connected to each other        and form the fifth shaft of the transmission,    -   a carrier of the first planetary gearset and a ring gear of the        third planetary gearset are permanently connected to each other        and form the sixth shaft of the transmission,    -   a sun gear of the second planetary gearset and a ring gear of        the fourth planetary gearset are permanently connected to each        other and form the seventh shaft of the transmission,    -   a ring gear of the second planetary gear forms the eighth shaft        of the transmission,    -   the first shifting element is arranged within the power flow        between the third shaft and a housing of the transmission,    -   the second shifting element is arranged within the power flow        between the fourth shaft and the housing of the transmission,    -   the third shifting element is arranged within the power flow        between the first and fifth shaft of the transmission,    -   the fourth shifting element is arranged within the power flow        between the fifth and eighth shaft of the transmission, and    -   the fifth shifting element is arranged within the power flow        between either the fifth and seventh shaft or between the        seventh and eighth shaft of the transmission.

The multi-speed transmission according to the invention differs from themulti-speed transmission of the generic kind according to DE 10 2005 002337.1 in that the carrier of the second planetary gearset and the sungear of the third planetary gearset are permanently connected to eachother as the fifth shaft of the transmission, and the eighth shaft ofthe transmission is now formed by the ring gear of the second planetarygearset.

As in the generic multi-speed transmission according to DE 10 2005 002337.1, it is also applicable to the multi-speed transmission accordingto the invention that the multi-speed transmission according to theinvention that the first forward gear is produced by engaging the first,second, and third shifting elements; the second forward gear is producedby engaging the first, second, and fifth shifting elements; the thirdforward gear is produced by engaging the second, third, and fifthshifting elements; the fourth forward gear is produced by engaging thesecond, fourth, and fifth shifting elements; the fifth forward gear isproduced by engaging the second, third, and fourth shifting elements;the sixth forward gear is produced by engaging the third, fourth, andfifth shifting elements; the seventh forward gear is produced byengaging the first, third, and fourth shifting elements; the eighthforward gear is produced by engaging the first, fourth, and fifthshifting elements; and the reverse gear is produced by engaging thefirst, second, and fourth shifting elements.

Three of the four planetary gearsets are configured as so-callednegative planetary gearsets, whose respective planetary gears mesh withthe sun gear and ring gear of the respective planetary gearset. One ofthe four planetary gearsets—specifically, the second planetarygearset—is configured as a so-called positive planetary gearset withmeshing inner and outer planetary gears, wherein these inner planetarygears also mesh with the sun gear of this positive planetary gearset,and these outer planetary gears also mesh with the ring gear of thispositive planetary gearset. Regarding the spatial arrangement of thefour planetary gearsets in the housing of the transmission, anadvantageous configuration proposes that the four planetary gearsets bearranged in a sequential order of “first, fourth, second, thirdplanetary gearset”.

The spatial arrangement of the shifting elements of the multi-speedtransmission according to the invention inside the transmission housingis, in principle, limited only by the measurements and the externalshape of the transmission housing. Numerous suggestions regarding thespatial arrangement and construction design of the shifting elements canbe seen, for example, in the generic patent application of DE 10 2005002 337.1.

For example, in a variant of the shifting element arrangement favorablefor a standard transmission, it can be provided that the first andsecond shifting elements are arranged, with respect to the spatiallayout at least partially within an area located radially above thefirst and or fourth planetary gearsets, and that the third shiftingelement can be arranged from the spatial point of view axially betweenthe second and third planetary gearsets, and that the fourth shiftingelement is also arranged from the spatial point of view within an arealocated axially between the second and third planetary gearsets, if itis kinematically coupled directly to the second shaft of thetransmission, or that the fourth shifting element is arranged from thespatial point of view at least in part within an area located radiallyabove the second planetary gearset, if it is kinematically coupleddirectly to the sixth shaft of the transmission, and the fifth shiftingelement is also arranged, with respect for the spatial layout, eitherwithin an area located axially between the second and third planetarygearsets, or within an area located axially between the fourth andsecond planetary gearsets.

The embodiment of the multi-speed transmission according to theinvention produces transmission ratios that are particularly suitablefor passenger cars, with a large total transmission ratio spread inharmonic gear stepping. In addition, with the multi-speed transmissionaccording to the invention, the material requirements for constructionare comparatively small due to the small number of shifting elements,that is, two brakes and two clutches. In addition, the multi-speedtransmission also displays good efficiency in all gears, on one hand,due to the low drag loss, because only two shifting elements aredisengaged in each gear and, on the other hand, as a result of the lowgearing losses in the simply constructed individual planetary gearsets.

In addition, it is advantageously possible with the multi-speedtransmission according to the invention to initiate driving the vehicleusing a hydrodynamic converter, an external starting clutch, or alsowith other suitable external starting elements. It is also conceivableto enable a drive initiating process with a starting element that isintegrated into the transmission. Advantageously suitable for thisprocess is one of the two brakes, which is activated in the first andsecond forward gear and in the reverse gear.

In addition, the multi-speed transmission according to the invention isdesigned such that it is adaptable to different power train arrangementsin both power flow directions and from a spatial point of view. It ispossible, for example, without special constructive measures, to arrangethe transmission input and output alternately co-axially or axiallyparallel with respect to each other.

For example, for use with input and output shafts that run co-axiallywith respect to each other, it is practical that the first planetarygearset is the planetary gearset that faces the engine driving theinventive planetary gearset group of the transmission. Depending on thespatial arrangement of the five shifting elements inside thetransmission housing, it can be provided that, in each case, no morethan one shaft of the transmission passes in an axial direction throughthe center the four planetary gearsets. In relation to the shiftingelement arrangement described above, in connection with the arrangementof the four planetary gearsets co-axially side-by-side in the sequentialorder of “first, fourth, second, third planetary gearset” and thearrangement of the first and second shifting elements near the driveinput, only one shaft, that is, the first shaft or the input shaft ofthe transmission, passes in an axial direction through the center of thefirst and fourth planetary gearsets. The constructive design of thepressurizing medium and lubricant supply to the servo unit units of theindividual shifting elements is correspondingly simple.

For use with input and output shafts that are axially parallel or are atan angle with respect to each other, the first or the third planetarygearset can be arranged on the side of the transmission housing facingthe drive motor and is functionally connected to the drive shaft. If thefirst planetary gearset faces the transmission drive, it can beprovided—as with the co-axial arrangement of the input and outputshafts—depending on the spatial arrangement of the five shiftingelements inside the transmission housing—that no more than one shaft ofthe transmission passes in an axial direction through each of the fourplanetary gearsets, in particular that only one shaft, specifically thefirst shaft of the transmission, passes through the first and fourthplanetary gearset.

On the other hand, if the third planetary gearset faces the drive of thetransmission, and the input and output shafts are not arrangedco-axially with respect to each other, no shaft of the transmission hasto pass in an axial direction through the first and fourth planetarygearsets. In connection with the arrangement, cited above, of the third,fourth, and fifth shifting elements, only one shaft, that is, the firstshaft or the input shaft of the transmission, passes in an axialdirection through the center of only two of the four planetary gearsets,that is, the second and third planetary gears sets.

In any case, the third shaft of the transmission, which is formed insections by the sun gears of the first and fourth planetary gearsets,can be rotatably mounted on a hub that is affixed to the housing. If thefirst planetary gearset faces the input of the transmission, the citedhub, which is affixed to the housing, is an element of the housing wallon the input side; otherwise it is an element of the housing wallopposite the drive engine.

The invention is described in more detail below based on examplesdepicted in the drawings. The same or comparable components are providedwith the same reference numerals. In the drawings:

FIG. 1 shows a schematic representation of an exemplary embodiment of amulti-speed transmission according to the invention;

FIG. 2 shows a schematic representation of a second exemplary embodimentof a multi-speed transmission according to the invention based on thegear arrangement according to FIG. 1;

FIG. 3 shows a schematic representation of a third example of amulti-speed transmission according to the invention based on the geararrangement according to FIG. 1;

FIG. 4 shows an exemplary shift pattern for a multi-speed transmissionaccording to FIGS. 1, 2, and 3;

FIG. 5 shows a schematic representation of a fourth example of amulti-speed transmission according to the invention based on the geararrangement according to FIG. 1;

FIG. 6 shows a schematic representation of a fifth example of amulti-speed transmission according to the invention based on the geararrangement according to FIG. 5;

FIG. 7 shows a schematic representation of a sixth example of amulti-speed transmission according to the invention based on the geararrangement according to FIG. 5, and

FIG. 8 shows an exemplary shift pattern for the multi-speed transmissionaccording to FIGS. 5, 6, and 7.

FIG. 1 shows a first exemplary embodiment of a multi-speed transmissionaccording to the invention in schematic representation. The transmissioncomprises an input shaft AN and an output shaft AB, as well as fourplanetary gearsets RS1, RS2, RS3, RS4 and five shifting elements A, B,C, D, E, which are all arranged in a housing GG of the transmission. Inthis exemplary embodiment, the four planetary gearsets RS1, RS2, RS3,RS4, are arranged co-axially, one after the other, in an axial directionin the sequential order of “RS1, RS4, RS2, RS3”. The planetary gearsetsRS1, RS3 and RS4 are configured as simple negative planetary gearsets.As is generally known, a negative planetary gearset features planetarygears that mesh with sun and ring gears of this planetary set. The ringgears of the planetary gearsets RS1, RS3, RS4, are identified with HO1,HO3 and HO4; the sun gears are identified with SO1, SO3 and SO4; theplanetary gears are identified with PL1, PL3 and PL4; and the carriers,on which the planetary gears are rotatably mounted, are identified withST1, ST3 and ST4. The planetary gearset RS2 is configured as a simplepositive planetary gearset within double planetary design. As isgenerally known, a positive planetary gearset features inner and outerplanetary gears that mesh with each other, wherein the inner planetarygears also mesh with the sun gear of this planetary gearset, and theouter planetary gears also mesh with the ring gear of this planetaryset. The ring gear of the planetary gearset RS2 is identified with HO2,the sun gear is identified with SO2, the inner planetary gears areidentified with PL2 i, the outer planetary gears are identified with PL2a, and the carrier, on which the inner and outer planetary gears PL2 i,PL2 a are rotatably mounted, is identified with ST2. The shiftingelements A and B are configured as brakes, which in the exemplaryembodiment presented herein are both configured as non-positive,shiftable disk brakes, which in another embodiment can, of course, beconfigured as non-positive shiftable band brakes, for example, and alsoas non-positive shiftable claw brakes or conical brakes. The shiftingelements C, D and E are configured as clutches, which in the exemplaryembodiment shown are all configured as non-positive, shiftable diskclutches, and can naturally also be configured, for example, asnon-positive shiftable claw or conical clutches. With these fiveshifting elements A to E, eight forward gears and at least one reversegear can be implemented by selective shifting. The multi-speedtransmission according to the invention therefore features at leasteight rotary shafts that are identified with reference numerals 1 to 8.

With regard to the kinematic coupling of the individual elements of thefour planetary gearsets RS1, RS2, RS3, RS4 to each other and to theinput and output shafts AN, AB the following is provided: the carrierST4 of the fourth planetary gearset and the input shaft AN arepermanently connected to each other and form the shaft 1. The carrierST3 of the third planetary gearset RS3 and the output shaft AB arepermanently connected with each other and form the shaft 2. The sun gearSO1 of the first planetary gearset RS1 and the sun gear SO4 of thefourth planetary gearset RS4 are permanently connected to each other andform the shaft 3. The ring gear HO1 of the first planetary gearset RS1forms the shaft 4. The carrier ST2 of the second planetary gearset RS2and the sun gear SO3 of the third planetary gearset RS3 are permanentlyconnected to each other and form the shaft 5. The carrier ST1 of thefirst planetary gearset RS1 and the ring gear HO3 of the third planetarygearset RS3 are permanently connected to each other and form the shaft6. The sun gear SO2 of the second planetary gearset RS2 and the ringgear HO4 of the fourth planetary gearset RS4 are permanently connectedto each other and form the shaft 7. The ring gear HO2 of the secondplanetary gearset RS2 forms the shaft 8.

With regard to the kinematic coupling of the five shifting elements A toE to the above described shafts 1 to 8 of the transmission, themulti-speed transmission according to FIG. 1 provides the following: thebrake A is arranged as first shifting element within the power flowbetween the shaft 3 and a housing GG of the transmission. The brake B isarranged as second shifting element within the power flow between theshaft 4 and the housing GG. The clutch C is arranged as third shiftingelement within the power flow between the shaft 1 and the shaft 5. Theclutch D is arranged as fourth shifting element between the shaft 2 andthe shaft 8. The clutch E is arranged as fifth shifting element withinthe power flow between the shaft 7 and the shaft 8 and locks the secondplanetary gearset RS2 in the engaged or shifted state.

In the exemplary embodiment shown in FIG. 1, the first planetary gearsetRS1 is the gearset of the transmission that is near the input, and thethird planetary gearset RS3 is the gearset near the output of thetransmission, wherein the input shaft AN and the output shaft AB arearranged, for example, co-axially with respect to each other. It isobvious to the person skilled in the art that this transmission can bemodified without great effort so that the input and output shafts are nolonger arranged co-axially with respect to each other, but, for example,axially parallel or at an angle with respect to each other. With anarrangement of this type, the person skilled in the art will, if needed,arrange the input of the transmission close to the third planetarygearset RS3, that is, on the side of the third planetary gearset RS3that faces away from the planetary gearset RS1.

In principle, the spatial arrangement of the shifting elements withinthe transmission is optional in the exemplary embodiment of amulti-speed transmission according to the invention shown in FIG. 1 andis limited only by the measurements and the external shape of thetransmission housing GG.

In the exemplary embodiment shown in FIG. 1, the two brakes A, B arearranged, with respect to the spatial layout, within the area of thefirst planetary gearset RS1, which is near the input in this case, andaxially side by side, wherein the kinematic connection of the two brakesA, B to the first planetary gearset RS1 requires that the brake B benearer to the fourth planetary gearset RS4, which is adjacent to thefirst planetary gearset RS1, than to the brake A or that the brake A bearranged nearer to the drive of the transmission than the brake B. Withrespect to the spatial layout, the brake B is at least partiallyarranged within an area located radially above the first planetarygearset RS1, and the brake A is arranged correspondingly on the side(near the input) of the first planetary gearset RS1 that faces away fromthe fourth planetary gearset RS4. An internal disk carrier of the brakeA forms a section of the shaft 3 of the transmission and is connected ina rotationally fixed manner to the sun gear SO1 of the first planetarygearset RS1 on the side of the first planetary gearset RS1 that facesaway from the fourth planetary gearset RS4. The shaft 3 is configured bysections as a kind of sun shaft that connects the sun gears SO1, SO4 ofthe planetary gearsets RS1,RS4 to each other. The shaft 3 can therein berotatably mounted on either the input shaft AN or a hub (not shown inmore detail in FIG. 1) that is attached to the transmission housing. Aninterior disk carrier of the brake B forms a section of the shaft 4 ofthe transmission and is attached in a rotationally fixed manner to thering gear HO1 of the first planetary gearset RS1. The external diskcarriers of the brakes A and B can each be integrated in the housing GGor also configured as separate components, which are then attached in arotationally fixed manner to the housing GG. The servo unit unitsnecessary for actuating the friction elements of the two brakes A, B arenot represented in detail in FIG. 1 for the sake of simplicity and can,for example, be mounted in the transmission housing GG or a housingcover that is affixed on the transmission housing.

The person skilled in the art will modify this example of spatialarrangement of the two brakes A, B as needed, without particularinventive effort. The brake A can be arranged, at least in part,radially above the first planetary gearset RS1, and the brake B can bearranged, at least in part, radially above the fourth planetary gearsetRS4. In yet another embodiment, the two brakes A, B can, for example, bearranged on the side of the first planetary gearset RS1 that faces awayfrom the fourth planetary gearset RS4, radially one above the other andaxially adjacent to the first planetary gearset RS1, wherein the brakeB, for example, is then arranged on a larger diameter than the brake A.

As can also be seen from FIG. 1, the clutches C and D—at least theirdisk packets—are arranged from a spatial point of view within an arealocated axially between the second and third planetary gearsets RS2,RS3, while the clutch E—at least its disk packet—is arranged from aspatial point of view within an area located axially between the fourthand second planetary gearset RS4, RS2. The servo units of the threeclutches C, D, E, required to activate these disk sets, are not shown indetail in FIG. 1 for the purpose of simplification.

In the example, the clutches C, D are arranged essentially axiallyadjacent, with the disk set of the clutch D is arranged at a largerdiameter than the disk set of the clutch C. The clutch C is hereinarranged axially adjacent to the second planetary gearset RS2, thereforecloser to the second planetary gearset RS2 than to clutch D.Accordingly, the clutch D is arranged axially adjacent to the thirdplanetary gearset RS3, therefore closer to the third planetary gearsetRS3 than the clutch C. An external disk carrier of the clutch C isconnected to the carrier ST2 of the planetary gearset RS2 on the side ofthe disk set of the clutch C that faces the second planetary gearset RS2and is also connected to the sun gear SO3 of the third planetary gearsetRS3 on the side of the disk set of the clutch C that faces the thirdplanetary gearset RS3 and, therefore, can be identified as a section ofthe shaft 5 of the transmission. An internal disk carrier of the clutchC is connected to the carrier ST4 of the fourth planetary gearset RS4and to the input shaft AN of the transmission and can therefore also beidentified as a section of the shaft 1 of the transmission. In a simplemanner, the servo unit required for actuating the disk set of the clutchC can be mounted in an axially displaceable manner on the internal diskcarrier of the clutch C and, therefore, rotates constantly at therotational speed of the shaft 1, for example, the input shaft AN.However, the servo unit of the clutch C can be preferably arrangedinside a cylindrical chamber formed by the external disk carrier of theclutch C and mounted in an axially displaceable manner on this externaldisk carrier of clutch C and, therefore, constantly rotates with therotational speed of the shaft 5. In order to compensate for therotational pressure of the rotating pressure chamber of this servo unit,the clutch C can have a known dynamic pressure compensation.

An external disk carrier of the clutch D is connected on the side of thedisk set of the clutch D facing the third planetary gearset RS3 of thedisk set of the clutch D to the carrier ST3 of this planetary gearsetRS3 and, via this carrier ST3, also to the output shaft AB of thetransmission and, therefore, can be identified as a section of the shaft2 of the transmission. An internal disk carrier of the clutch D isconnected, on the side of the disk set of the clutch D that faces thesecond planetary gearset RS2 to the ring gear HO2 of the secondplanetary gearset RS2 and can therefore also be identified as a sectionof the shaft 8 of the transmission. Over its axial length, this shaft 8completely overlaps the clutch C. The servo unit necessary to actuatethe disk set of the clutch D can be arranged in a simple manner insidethe cylindrical chamber formed by the external disk carrier of theclutch D and can be mounted in an axially displaceable manner on theexternal disk carrier of the clutch D and, therefore, can constantlyrotate at the rotational speed of the shaft 2 or the rotational speed ofthe output. However, it can, for example, also be provided that theservo unit of the clutch D is mounted in an axially displaceable manneron the internal disk carrier of the clutch D and, therefore, rotatesconstantly at the rotational speed of the shaft 8. In order tocompensate for the rotational pressure of the rotating pressure chamberof the servo unit of the clutch D, known dynamic pressure compensationcan be provided.

For the person skilled in the art, it is easy to see that, differingfrom FIG. 1, in another embodiment of the transmission, the disk set ofthe clutch D can also be arranged, at least in part, radially above thedisk set of the clutch C, wherein the axial distance for installation ofthe transmission is shortened.

In the exemplary embodiment shown in FIG. 1, the clutch E, which locksthe second planetary gearset RS2 in the engaged or shifted state, isarranged within an area located axially between the second planetarygearset RS2 and the fourth planetary gearset RS4, therein axiallydirectly adjacent to the secondary planetary gearset RS2. An externaldisk carrier of the clutch E is connected to the ring gear HO2 of thesecond planetary gearset RS2 on its side facing the planetary gearsetand, therefore, forms an additional section of the shaft 8 of thetransmission. An internal disk carrier of the clutch E is connected tothe sun gear SO2 of the second planetary gearset RS2 and to the ringgear HO4 of the fourth planetary gearset RS4, and can therefore beidentified as a section of the shaft 7 of the transmission. The servounit required for the actuation of the disk set of the clutch E can besimply mounted in an axially displaceable manner on the internal diskcarrier of the clutch E and, therefore, rotates constantly at therotational speed of the shaft 7. The servo unit of the clutch E can,however, also be mounted in an axially displaceable manner on theexternal disk carrier of the clutch E and, therefore, rotates constantlyat the rotational speed of the shaft 8. In order to compensate for therotational pressure of the pressure chamber of the servo unit of theclutch E, known dynamic pressure compensation can be provided.

According to the gearset arrangement corresponding to the sequentialorder of “RS1-RS4-RS2-RS3” of the four planetary gearsets RS1, RS2, RS3,RS4, and corresponding to the arrangement of the three clutches C, D, Ewithin an area located axially between the fourth and third planetarygearset RS4, RS3, the shaft 6 of the transmission completely overlapswithin its axial length the fourth planetary gearset RS4, the clutch E,the second planetary gearset RS2, and the two clutches C and D. At thesame time, the shaft 6 radially encloses the shaft 7 and the shaft 8 anda section of the shaft 2.

It is expressly pointed out that the arrangement of the five shiftingelements A, B, C, D, E stated above is to be considered as an exampleonly. If required, the person skilled in the art will modify, in thisexample, the spatial arrangement of the five shifting elements A, B, C,D, E; numerous proposals for this can be seen, for example, in thepatent application of the generic kind DE 10 2005 002 337.1.

Based on the consideration that the clutch E, being the fifth shiftingelement of the transmission, locks the second planetary gearset RS2 in ashifted or engaged state, two other possibilities of two exemplaryembodiments of a multi-speed transmission according to the invention forlocking the cited second planetary gearset RS2 by way of the citedclutch E are shown in the following. FIG. 2 illustrates a secondexemplary embodiment and FIG. 3 shows a third exemplary embodiment of amulti-speed transmission according to the invention, again in simplifiedschematic presentation, both based on the first exemplary embodiment ofthe inventive transmission explained in detail above with regard to FIG.1.

It can be easily seen from FIG. 2 that the only difference, relative tothe transmission kinematics of the second exemplary embodiment shownhere, of a multi-speed transmission according to the invention incomparison to FIG. 1, is that the clutch E is now arranged within thepower flow between the shaft 5 and the shaft 7. In the shifted orengaged state, the clutch E now therefore connects the carrier ST2 andthe sun gear SO2 of the second planetary gear RS2.

It can also be seen in FIG. 2 that the most important difference in theshifting element arrangement inside the housing GG in the secondexemplary embodiment of a multi-speed transmission, shown herein, incomparison with FIG. 1 is that the clutch E is now arranged with respectto the spatial layout within an area located axially between the secondand third planetary gearsets RS2, RS3, and therein axially directlyadjacent to the second planetary gearset RS2, wherein the clutch C isaxially adjacent to the clutch E on the side of the clutch E that facesaway from the planetary gearset RS2. On its side facing the planetarygearset RS2, the external disk carrier of the clutch E is connected tothe carrier ST2 of this planetary gearset, and on its side facing awayfrom the second planetary gearset RS2 to the external disk carrier ofthe clutch C, and via this external disk carrier of the clutch C, to thesun gear SO3 of the third planetary gearset RS3, thereby forming asection of shaft 5 of the transmission. The internal disk carrier of theclutch E is connected to the sun gear SO2 of the second planetarygearset RS2, and via this sun gear SO2, to the ring gear HO4 of thefourth planetary gearset RS4, thereby forming a section of shaft 7 ofthe transmission. A servo unit of the clutch E—not depicted in FIG. 2for the purpose of simplification—can be simply mounted in an axiallydisplaceable manner on the internal disk carrier of the clutch E and,therefore, rotates constantly at the rotational speed of the shaft 7;however, it can of course also be mounted in an axially displaceablemanner on the external disk carrier of the clutch E to therefore rotateconstantly at the rotational speed of the shaft 5. Here too, of course,known dynamic pressure compensation can also be provided for the servounit of the clutch E.

As is also clearly seen in FIG. 2, it is advantageously possible interms of manufacturing technology, to provide a common disk carrier forthese to clutches C, E through the kinematic connection of the twoclutches C and E to the shaft 5. If the disk sets of the two clutches C,E, as in the exemplary embodiment shown here (as an example), arearranged axially side-by-side at the same diameter, a common diskcarrier of this kind can be configured as an external disk carrier forboth clutches C, E, which, together with the carrier ST2 of the secondplanetary gearset RS2, or together with the sun gear SO3 of the thirdplanetary gearset RS3, forms a preassembled arrangement. If required,however, the person skilled in the art will also consider other suitableconstructive configurations of a common disk carrier for both clutchesC, E. In the same manner, if needed in FIG. 2, the person skilled in theart will modify the example of spatial arrangement of the clutch Drelative to the two clutches C, E and arrange the disk set of the clutchD, for example, at least in part radially above the disk set of theclutch D, or at least radially above the second planetary gearset RS2.

The exemplary embodiment of the inventive transmission, shown in FIG. 2,are reproduced, in regard to the spatial arrangement and constructivedesign of the shifting elements of FIG. 1, so that this description doesnot have to be repeated here.

It can clearly be seen in FIG. 3 that the only difference intransmission kinematics in the third exemplary embodiment of amulti-speed transmission according to the invention shown here incomparison with FIG. 1 is that the clutch E is now arranged within thepower flow between the shaft 5 and the shaft 8.

In the shifted or engaged state, the clutch E now therefore connects thecarrier ST2 and the ring gear HO2 of the planetary gearset RS2. In thethird exemplary embodiment of the inventive transmission shown herein,the spatial arrangement of the shifting elements and the planetarygearsets relative to each other, as well as the constructive design ofthe shifting elements and planetary gearsets were largely taken fromFIG. 1, so that the following description can be limited to the detailsapplicable to clutch E.

As can be seen in FIG. 3, the clutch E is now arranged with respect tothe spatial layout within an area located axially between the second andthird planetary gearsets RS2, RS3, and also axially adjacent to thesecond planetary gearset RS2, similar to the arrangement in FIG. 2. Incontrast with FIG. 2, the disk set of the clutch E is now arranged withrespect to the spatial layout within an area located radially above theclutch C. The external disk carrier of the clutch E forms a section ofthe shaft 8 of the transmission, is now connected at its side facing thesecond planetary gearset RS2 to the ring gear HO2 of that gearset, andis now also connected at its side facing away from the second planetarygearset RS2 to the internal disk carrier of the clutch D. The internaldisk carrier of the clutch E now forms an additional section of theshaft 5 of the transmission and is connected to the carrier ST2 of thesecond planetary gearset RS2, the external disk carrier of the clutch C,and the sun gear SO3 of the third planetary gearset RS3. A servo unit ofthe clutch E, which is intended for the actuation of the disk set of theclutch E—which is not illustrated in FIG. 3, for the purpose ofsimplification—can easily be mounted in an axially displaceable manneron the internal disk carrier of the clutch E to therefore constantly atthe rotational speed of the shaft 5. The servo unit of the clutch E canalso be mounted in an axially displaceable manner on the external diskcarrier of the clutch E to therefore rotate constantly at the rotationalspeed of the shaft 8.

It is obvious to the person skilled in the art that a common diskcarrier can be respectively provided in an advantageous way, in terms ofconstruction technology, for both the clutches C and E and the clutchesD and E due to the special kinematic connection of the clutch E to theshafts 5 and 8 of the transmission. As an example of this, in FIG. 3, acommon disk carrier of this type is designed for the clutches C, E as aninternal disk carrier for the clutch E, a common disk carrier of thistype for the clutches D, E as external disk carrier for the clutch E,and as internal disk carrier for the clutch D. If needed, a personskilled in the art will naturally also consider other suitableconstructive designs for the disk carriers of the three clutches C, D,E.

In other respects, the exemplary embodiments shown in this context forFIG. 2 can also be transferred, at least analogously, to the exemplaryembodiment of a transmission according to the invention shown in FIG. 3.

FIG. 4 illustrates a shift pattern, which can be provided for theinventive multi-speed transmission according to FIGS. 1, 2, and 3. Ineach gear, three shifting elements are engaged, and two shiftingelements are disengaged. In addition to the shifting logic, examples ofvalues of the respective transmission ratios in individual gear ratios ican be obtained along with the progressive ratio codes φ determined fromthem. The specified ratios i are obtained from the (typical) stationarytransmission ratios of the four planetary gearsets RS1, RS2, RS3, RS4 ofnegative 2.00, positive 2.60, negative 3.70, and negative 2.00. Inaddition, it can be seen from the shift pattern that double shifts orrange shifts can be avoided with sequential shifting, because twoadjacent gears in the shifting logic use two shifting elements incommon. The sixth gear is configured as a direct gear.

The first forward gear results by engaging the brakes A and B and theclutch C, the second forward gear results by engaging the brakes A and Band the clutch E, the third forward gear results by engaging the brake Band the clutches C and E, the fourth forward gear results by engagingthe brake B and the clutches D and E, the fifth forward gear results byengaging the brake B and the clutches C and D, the sixth forward gearresults by engaging the clutches C, D, and E, the seventh forward gearresults by engaging the brake A and the clutches C and D, and the eighthforward gear results by engaging the brake A and the clutches D and E.As can also be seen from the shift pattern, the reverse gear results byengaging the brakes A and B and the clutch D.

According to the invention, it is possible to initiate driving the motorvehicle with a shifting element integrated into the transmission. Ashifting element that is used in both the first forward gear and in thereverse gear, the brake A or the brake B is particularly suitable forthis purpose in this case. Advantageously, both of these brakes, A, Bare also required in the second forward gear. If the brake B is used asthe starting element integrated into the transmission, it is evenpossible to initiate driving in the first five forward gears and thereverse gear. As can be seen from the shift pattern, the clutch C canalso be used when starting in a forward direction and the clutch D canbe used as an internal transmission starting element for initiatingdriving in a reverse direction.

FIG. 5 now shows a fourth exemplary embodiment of a multi-speedtransmission according to the invention based on the first exemplaryembodiment of a transmission according to the invention as explained indetail above with regard to FIG. 1. It is easy to see from FIG. 5 thatthe only difference with regard to the transmission kinematics of thefourth exemplary embodiment illustrated herein when compared to FIG. 1consists in that the clutch D, as the fourth shifting element of thetransmission, is now arranged within the power flow between the shaft 6and the shaft 8 of the transmission. In a shifted or engaged state, theclutch D now connects the ring gear of the planetary gearset RS2 to thecarrier ST1 of the first planetary gearset RS1 and the ring gear HO3 ofthe third planetary gearset RS3.

It is also easy to see in FIG. 5 that the spatial arrangement of thecomponents of the transmission relative to each other within thetransmission housing, except for the details applying to clutch D, isthe same as that of FIG. 1. The following description, therefore, can belimited to these differing details. As can be seen in FIG. 5, the clutchD is axially arranged as in FIG. 1, with respect to the spatial layout,within an area located between the second and third planetary gearsetsRS2, RS3. The person skilled in the art will be able without problem,however, to slightly modify this spatial arrangement of the clutch D, ifneeded, and arrange the disk set of the clutch D, for example, within anarea located radially above the second planetary gearset RS2, or alsowithin an area located axially between the second and fourth planetarygearsets RS2, RS4, and radially above the clutch E.

According to FIG. 5, the external disk carrier of the clutch D now formsa section of the shaft 6 of the transmission and is connected to thering gear HO3 at its side facing the third planetary gearset RS3, and tothe carrier ST1 of the first planetary gearset RS1 at its side facingaway from the third planetary gearset RS3. Similar tp FIG. 1, theinternal disk carrier of the clutch D forms a section of the shaft 8 ofthe transmission and is connected to the ring gear HO2 at its sidefacing the second planetary gearset RS2, and to the external diskcarrier of the clutch E via this ring gear HO2. A servo unit of theclutch D—not shown in detail in FIG. 5—for the actuation of its disk setcan be arranged in a simple manner inside the cylindrical chamber formedby the external disk carrier of the clutch D and can be mounted in anaxially displaceable manner on the said external disk carrier of theclutch D, to rotate constantly at the rotational speed of the shaft 6.The servo unit of the clutch D, however, can also be mounted in anaxially displaceable manner on the internal disk carrier of the clutch Dand to rotate constantly at the rotational speed of the shaft 8. Theservo unit of the clutch D can feature a known dynamic pressurecompensation.

Based on the consideration that the clutch E locks the second planetarygearset RS2 in a shifted or engaged state as the fifth shifting elementof the transmission, the following two exemplary embodiments of amulti-speed transmission according to the invention illustrate two otherpossibilities for locking the second planetary gearset RS2 by way of theclutch E. FIG. 6 shows a fifth exemplary embodiment and FIG. 7 shows asixth exemplary embodiment of a multi-speed transmission according tothe invention, also in simplified schematic representation, both basedon the fourth exemplary embodiment of an inventive transmissionexplained with reference to FIG. 5.

It can be clearly seen in FIG. 6 that the only difference with regard totransmission kinematics in the fifth exemplary embodiment of amulti-speed transmission according to the invention, illustrated herein,in comparison with FIG. 5 is that the clutch E is now arranged withinthe power flow between the shaft 5 and the shaft 7. In the shifted orengaged state, the clutch E now connects other the carrier ST2 and thesun gear SO2 of the planetary gearset RS2.

It is also obvious in FIG. 6 that the spatial arrangement of thecomponents of the transmission relative to each other within thetransmission housing is the same as that of FIG. 2, with the exceptionof the description applying to clutch D. The following description cantherefore be limited to these differing details. As seen in FIG. 6, theclutch D is now arranged from a spatial point of view within an arealocated radially above the second planetary gearset RS2. This kind ofarrangement option has already been discussed in connection with thedescription of FIG. 5.

It is clearly seen in FIG. 7 that the only difference with regard to thetransmission kinematics in the sixth exemplary embodiment of amulti-speed transmission according to the invention, illustrated herein,in comparison with FIG. 5 is that the clutch E is now arranged withinthe power flow between the shaft 5 and the shaft 8. In the shifted orengaged state, the clutch E, therefore, now connects the carrier ST2 andthe ring gear HO2 of the second planetary gearset RS2.

It is also clearly seen in FIG. 7 that the spatial arrangement of thecomponents of the transmission relative to each other within thetransmission housing remains unchanged, except for the descriptionpertaining to clutch D. The following, therefore, will be limited tothese deviating description. As seen in FIG. 7, the external diskcarrier of the clutch D now forms a section of the shaft 6 of thetransmission and is connected to the ring gear HO3 of that gearset onits side facing the third planetary gearset RS3, and to the carrier ST1of the first planetary gearset RS1 on its side facing away from thethird planetary gearset RS3. Similar to FIG. 3, the internal diskcarrier of the clutch D forms a section of the shaft 8 of thetransmission and is connected to the external disk carrier of the clutchE on its side facing the planetary gearset RS2 and to the ring gear HO2of the second planetary gearset RS2. A servo unit of the clutch D—notshown in detail in FIG. 7—can be arranged in a simple manner inside thecylindrical chamber formed by the external disk carrier of the clutch Dand can be mounted in an axially displaceable manner on the externaldisk carrier of the clutch D to rotate constantly at the rotationalspeed of the shaft 6, but can be displaceably mounted on the internaldisk carrier of the clutch D to rotate constantly at the rotationalspeed of the shaft 8. The servo unit of the clutch D can also beprovided with known dynamic pressure compensation.

Finally, in FIG. 8 illustrates a shift pattern that could be providedfor the inventive multi-speed transmission according to the FIGS. 5, 6and 7. In each gear, three shifting elements are engaged and twoshifting elements are disengaged. In addition to the shifting logic,examples of values for the respective transmission ratios in individualgear ratios i can be obtained along with the progressive ratio codes φdetermined from them. The specified ratios i are obtained from the(typical) stationary transmission ratios of the four planetary gearsetsRS1, RS2, RS3, RS4 of negative 2.00, positive 2.00, negative 3.70, andnegative 2.00. In addition, it can be seen from the shift pattern thatdouble shifts or range shifts can be avoided with sequential shifting,because two adjacent gears in the shifting logic use two shiftingelements in common. It can be clearly seen in FIG. 8 that the shiftinglogic is identical to that of FIG. 4, which is why it is not necessaryto provide a more detailed description at this time. According to thedifferent kinematic connections of the clutch D in comparison with thegearset diagrams illustrated in FIGS. 1, 2, and 3, and the slightlychanged stationary transmission ratios of the second planetary gearsetRS2 that are reasonable in this context, slightly different ratios i andprogressive ratio codes φ are obtained for the gearset diagramsaccording to FIGS. 5, 6, and 7 in comparison with FIG. 4.

The following also applies to all of the previously illustrated ordescribed exemplary embodiments of a multi-speed transmission accordingto the invention.

According to the invention, different gear transitions can be produced,even with the same gear gearbox diagram, depending on the stationarygearing multiplication, which makes it possible to have variationsspecific to use or vehicle:

It is also possible to provide additional one-way clutches at anysuitable position in the multi-speed transmission, for example, betweena shaft and the housing, or in order to connect two shafts, ifnecessary.

An axle differential and/or a distributor differential can be arrangedon either the input side or the output side.

In an advantageous further development, the input shaft AN can beseparated, if needed, by coupling element from a drive motor, wherein ahydrodynamic converter, a hydraulic clutch, a dry starting clutch, a wetstarting clutch, a magnetic particle clutch, or a centrifugal clutch canbe used as such a coupling element. It is also possible to arrange adriving element of this kind within the power flow behind thetransmission, whereby in this case, the input shaft AN is permanentlyconnected to the crankshaft of the drive motor.

In addition, the multi-speed transmission according to the inventionprovides the possibility of arranging a torsional vibration damperbetween the drive motor and the transmission.

Within the scope of an additional embodiment of the invention, a wearfree brake, such as a hydraulic or electric retarder, or the like can bearranged on the input shaft AN or the output shaft AB, which isparticularly important for use in commercial vehicles. In addition,power take off can be provided on each shaft, preferably on the inputshaft AN or the output shaft AB, in order to drive additional units oneach shaft.

The shifting elements used can be configured as power-shifting clutchesor brakes. In particular, non-positive clutches or brakes, such as diskclutches, band brakes and/or conical clutches, can be used. In addition,non-positive brakes and or/clutches, such as synchronizations or clawclutches, can be used as shifting elements.

A further advantage of the multi-speed transmission described herein isthat an electric machine can also be affixed to each shaft as agenerator and/or auxiliary main engine.

Any constructive design, in particular every spatial arrangement of theplanetary sets and the shifting elements per se, as well as with respectto each other, and insofar as technically practical, can be includedunder the scope of the protection of the claims, without influencing thefunction of the transmission as specified in the claims, even if thesedesigns are not explicitly presented in the Figures or in thespecification.

REFERENCE NUMERALS

-   -   1 first shaft    -   2 second shaft    -   3 third shaft    -   4 fourth shaft    -   5 fifth shaft    -   6 sixth shaft    -   7 seventh shaft    -   8 eighth shaft    -   A first shifting element, first brake    -   B second shifting element, second brake    -   C third shifting element, first clutch    -   D fourth shifting element, second clutch    -   E fifth shifting element, third clutch    -   AB output shaft    -   AN input shaft    -   GG housing    -   RS1 first planetary gearset    -   HO1 ring gear of the first planetary gearset    -   SO1 sun gear of the first planetary gearset    -   ST1 carrier of the first planetary gearset    -   PL1 planetary gears of the first planetary gearset    -   RS2 second planetary gearset    -   HO2 ring gear of the second planetary gearset    -   SO2 sun gear of the second planetary gearset    -   ST2 carrier of the second planetary gearset    -   PL2 a outer planetary gears of the second planetary gearset    -   PL2 i inner planetary gears of the second planetary gearset    -   RS3 third planetary gearset    -   HO3 ring gear of the third planetary gearset    -   SO3 sun gear of the third planetary gearset    -   ST3 carrier of the third planetary gearset    -   PL3 planetary gears of the third planetary gearset    -   RS4 fourth planetary gearset    -   HO4 ring gear of the fourth planetary gearset    -   SO4 sun gear of the fourth planetary gearset    -   ST4 carrier of the fourth planetary gearset    -   PL4 planetary gears of the fourth planetary gearset    -   i transmission ratio    -   φ progressive ratio

1-42. (canceled)
 43. A multi-speed automatic transmission of a planetarydesign for a motor vehicle, the transmission comprising: an input shaft(AN, 1), an output shaft (AB, 2) and at least third, fourth, fifth,sixth, seventh and eighth shafts (3, 4, 5, 6, 7, 8); only first, second,third and fourth planetary gear sets (RS1, RS2, RS3, RS4); only first,second, third, fourth and fifth shifting elements (A, B, C, D, E) whoseselective engagement defines different gear ratios between the inputshaft (AN) and the output shaft (AB) such that first, second, third,fourth, fifth, sixth, seventh and eight forward gears and at least onereverse gear can be implemented; for each of the first, the second, thethird, the fourth, the fifth, the sixth, the seventh and the eightforward gear and at least one reverse gear, three of the first, thesecond, the third, the fourth and the fifth shifting elements (A, B, C,D, E) are engaged while a remaining two of the first, the second, thethird, the fourth and the fifth shifting elements (A, B, C, D, E) aredisengaged; and when shifting from a forward gear to one of a successivehigher and a successive lower forward gear, a single engaged one of thefirst, the second, the third, the fourth and the fifth shift elements isdisengaged and a single disengaged one of the first, the second, thethird, the fourth and the fifth shift elements is engaged.
 44. Themulti-speed transmission according to claim 43, wherein at least two sungears of two adjacent one of the first, the second, the third, thefourth planetary gear sets (RS1, RS2, RS3, RS4) are directly connectedwith one another by the third shaft (3).
 45. The multi-speedtransmission according to claim 43, wherein a ring gear of one of thefirst, the second, the third and the fourth planetary gear sets (RS1,RS2, RS3, RS4), which is located adjacent one end of the multi-speedtransmission, is connectable with a transmission housing by at least onebrake (B).
 46. The multi-speed transmission according to claim 43,wherein the first shifting element (A) is a first brake, the secondshifting element (B) is a second brake, the third, shifting element (C)is a first clutch, the fourth shifting elements (D) is a second clutch,and the fifth shifting elements (E) is a third clutch.
 47. Themulti-speed transmission according to claim 46, wherein the first clutch(C), the second clutch (D), and the third clutch (E) are allaccommodated within the multi-speed transmission closely adjacent oneanother between the second and the third planetary gear sets (RS2, RS3).48. The multi-speed transmission according to claim 43, wherein each ofthe third, the fourth, the fifth, the sixth, the seventh and the eighthshafts (3, 4, 5, 6, 7, 8) are rotatable.
 49. The multi-speedtransmission according to claim 46, wherein the first and the secondbrakes (A, B) are located adjacent one another and adjacent an end ofthe multi-speed transmission at which the input (AN) enters themulti-speed transmission, and the first brake, when engaged, couplesboth a sun gear of the first planetary gear set (RS1) and a sun gear ofthe fourth planetary gear set (RS4) to a transmission housing, and thesecond brake, when engaged, couples a ring gear of the first planetarygear set (RS1) to the transmission housing.
 50. The multi-speedtransmission according to claim 43, wherein the planet carrier of the ofthe first planetary gear set (RS1) is connected with a ring gear of thethird planetary gear set (RS3).
 51. The multi-speed transmissionaccording to claim 43, wherein the third shaft (3), the fifth shaft (5),the sixth shaft (6) and the seventh shaft (7) each directly couple twoof the planetary components of the first, the second, the third and thefourth planetary gear sets (RS1, RS2, RS3, RS4) with one another. 52.The multi-speed transmission according to claim 43, wherein the thirdshaft (3), the sixth shaft (6) and the seventh shaft (7) each directlycouple two of the planetary components of the first, the second, thethird and the fourth planetary gear sets (RS1, RS2, RS3, RS4) with oneanother, and the fifth shaft is rotatable and is connected with one ofthe planetary components of the third planetary gear set (RS3) and isalso connected with two of the first, the second, the third, the fourthand the fifth shifting elements (A, B, C, D, E).
 53. The multi-speedtransmission according to claim 43, wherein the fifth shaft is rotatableand is connected with one of the planetary components of the thirdplanetary gear set (RS3) and is also connected with two of the first,the second, the third, the fourth and the fifth shifting elements (A, B,C, D, E).
 54. The multi-speed transmission according to claim 43,wherein each of the first, the second, the third, the fourth and thefifth shifting elements (A, B, C, D, E) are coupled to at least one ofthe third shaft (3), the fourth shaft (4), the fifth shaft (5), theseventh shaft (7) and the eighth shaft (8) for supplying drive throughthe multi-speed automatic transmission from the input shaft (AN) to theoutput shaft (AB) for implementing the first, the second, the third, thefourth, the fifth, the sixth, the seventh and the eight forward gearsand the at least one reverse gear.
 55. The multi-speed transmissionaccording to claim 54, wherein each of the first, the second, the third,the fourth and the fifth shifting elements (A, B, C, D, E) are coupledto at least one of the third shaft (3), the fourth shaft (4), the fifthshaft (5), the seventh shaft (7) and the eighth shaft (8); and each ofthe first, the second, the third, the fourth and the fifth shiftingelements (A, B, C, D, E) are also coupled to one of a transmissionhousing and at least one of the planetary components of the first, thesecond, the third and the fourth planetary gear sets (RS1, RS2, RS3,RS4) for supplying drive through the multi-speed automatic transmissionfrom the input shaft (AN) to the output shaft (AB) for implementing thefirst, the second, the third, the fourth, the fifth, the sixth, theseventh and the eight forward gears and the at least one reverse gear.56. The multi-speed transmission according to claim 43, wherein only oneof the input shaft (AN, 1), the output shaft (AB, 2), the third shaft(3), the fourth shaft (4), the fifth shaft (5), the sixth shaft (6), theseventh shaft (7) and the eighth shaft (8) has no permanent connectionwith any of the first, the second, the third, the fourth and the fifthshifting elements (A, B, C, D, E).
 57. The multi-speed transmissionaccording to claim 43, wherein only one of the third, the fourth, thefifth, the sixth, the seventh and the eighth shafts (3, 4, 5, 6, 7, 8)has no permanent connected with any of the first, the second, the third,the fourth and the fifth shifting elements (A, B, C, D, E).
 58. Themulti-speed transmission according to claim 43, wherein each of thethird, the fourth, the fifth, the sixth, the seventh and the eighthshafts (3, 4, 5, 6, 7, 8) has a permanent connection to at least one ofthe first, the second, the third, the fourth and the fifth shiftingelements (A, B, C, D, E).
 59. A multi-speed automatic transmission of aplanetary design for a motor vehicle, the transmission comprising: aninput shaft (AN, 1), an output shaft (AB, 2) and at least third, fourth,fifth, sixth, seventh and eighth shafts (3, 4, 5, 6, 7, 8); only first,second, third and fourth planetary gear sets (RS1, RS2, RS3, RS4) eachhaving planetary components comprising a sun gear, a planet carriersupporting a plurality of planet gears and a ring gear; the input shaft(AN) being connected to a carrier of one of the first, the second, thethird and the fourth planetary gear sets (RS1, RS2, RS3, RS4) and theoutput shaft (AB) being connected to a carrier of another of the first,the second, the third and the fourth planetary gear sets (RS1, RS2, RS3,RS4); only first, second, third, fourth and fifth shifting elements (A,B, C, D, E) whose selective engagement defines different gear ratiosbetween the input shaft (AN) and the output shaft (AB) such that first,second, third, fourth, fifth, sixth, seventh and eight forward gears andat least one reverse gear can be implemented, and at least the firstelement (A) is a brake; each of the third shaft (3), the fourth shaft(4), the fifth shaft (5), the sixth shaft (6), the seventh shaft (7) andthe eighth shaft (3, 4, 5, 6, 7, 8) being coupled to at least one of theplanetary components of the first, the second, the third and the fourthplanetary gear sets (RS1, RS2, RS3, RS4); for each of the first, thesecond, the third, the fourth, the fifth, the sixth, the seventh and theeight forward gear and the at least one reverse gear, only three of thefirst, the second, the third, the fourth and the fifth shifting elements(A, B, C, D, E) are engaged while a remaining two of the first, thesecond, the third, the fourth and the fifth shifting elements (A, B, C,D, E) are disengaged; and when shifting from one forward gear to one ofa successive higher and a successive lower forward gear, a singleengaged one of the first, the second, the third, the fourth and thefifth shift elements is disengaged and a single disengaged one of thefirst, the second, the third, the fourth and the fifth shift elements isengage.
 60. The multi-speed transmission according to claim 59, whereineach of the third shaft (3), the fifth shaft (5), the sixth shaft (6)and the seventh shaft (7) directly couple two of the planetarycomponents of the first, the second, the third and the fourth planetarygear sets (RS1, RS2, RS3, RS4) with one another.
 61. The multi-speedtransmission according to claim 59, wherein the third shaft (3), thesixth shaft (6) and the seventh shaft (7) each directly couple two ofthe planetary components of the first, the second, the third and thefourth planetary gear sets (RS1, RS2, RS3, RS4) with one another, andthe fifth shaft (5) is rotatable and is connected with one of theplanetary components of the third planetary gear set (RS3) and is alsoconnected with two of the first, the second, the third, the fourth andthe fifth shifting elements (A, B, C, D, E).
 62. The multi-speedtransmission according to claim 59, wherein the first forward gearresults from engagement of the first shifting element (A), the secondshifting element (B) and the third shifting element (C); the secondforward gear results from engagement of the first shifting element (A),the second shifting element (B) and the fifth shifting element (E); thethird forward gear results from engagement of the second shiftingelement (B), the third shifting element (C) and the fifth shiftingelement (E); the fourth forward gear results from engagement of thesecond shifting element (B), the fourth shifting element (D) and thefifth shifting element (E); the fifth forward gear results fromengagement of the second shifting element (B), the third shiftingelement (C) and the fourth shifting element (D); the sixth forward gearresults from engagement of the third shifting element (C), the fourthshifting element (D) and the fifth shifting element (E); the seventhforward gear results from engagement of the first shifting element (A),the third shifting element (C) and the fourth shifting element (D); theeighth forward gear results from engagement of the first shiftingelement (A), the fourth shifting element (D) and the fifth shiftingelement (E); and the reverse gear results from engagement of the firstshifting element (A), the second shifting element (B) and the fourthshifting element (D).
 63. The multi-speed transmission according toclaim 59, wherein the first planetary gear set (RS1), the secondplanetary gear set (RS2), the third planetary gear set (RS3) and thefourth planetary gear set (RS4) are negative planetary gear sets. 64.The multi-speed transmission according to claim 59, wherein at least twosun gears of two adjacent one of the first, the second, the third, thefourth planetary gear sets (RS1, RS2, RS3, RS4) are directly connectedwith one another by the third shaft (3), and a ring gear of one of thefirst, the second, the third and the fourth planetary gear sets (RS1,RS2, RS3, RS4), which is located adjacent one end of the multi-speedtransmission, is connectable with a transmission housing by the firstelement (A) which is a brake.
 65. The multi-speed transmission accordingto claim 59, wherein the planet carrier of the of the first planetarygear set (RS1) is connected with a ring gear of the third planetary gearset (RS3), and the third shaft (3), the sixth shaft (6) and the seventhshaft (7) each directly couple two of the planetary components of thefirst, the second, the third and the fourth planetary gear sets (RS1,RS2, RS3, RS4) with one another, and the fifth shaft (5) is rotatableand is connected with one of the planetary components of the thirdplanetary gear set (RS3) and is also connected with two of the first,the second, the third, the fourth and the fifth shifting elements (A, B,C, D, E).
 66. The multi-speed transmission according to claim 59,wherein each of the first, the second, the third, the fourth and thefifth shifting elements (A, B, C, D, E) are coupled to at least one ofthe third shaft (3), the fourth shaft (4), the fifth shaft (5), and theeighth shaft (3, 4, 5, 6, 7, 8); and each of the first, the second, thethird, the fourth and the fifth shifting elements (A, B, C, D, E) arealso coupled to one of a transmission housing and at least one of theplanetary components of the first, the second, the third and the fourthplanetary gear sets (RS1, RS2, RS3, RS4) for supplying drive through themulti-speed automatic transmission from the input shaft (AN) to theoutput shaft (AB) for implementing the first, the second, the third, thefourth, the fifth, the sixth, the seventh and the eight forward gearsand the at least one reverse gear.
 67. A multi-speed automatictransmission of a planetary design for a motor vehicle, the transmissioncomprising: an input shaft (AN) and an output shaft (AB); first, second,third and fourth planetary gear sets (RS1, RS2, RS3, RS4); at leastthird, fourth, fifth, sixth, seventh and eighth rotatable shafts (3, 4,5, 6, 7, 8) and first, second, third, fourth and fifth shifting elements(A, B, C, D, E) whose selective engagement defines different gear ratiosbetween the input shaft (AN) and the output shaft (AB) such that eightforward gears and at least one reverse gear can be implemented; and whenshifting from one forward gear into one of a successive higher and asuccessive lower forward gear causes a single one of the first, thesecond, the third, the fourth and the fifth shift elements to disengageand a single one of the first, the second, the third, the fourth and thefifth shift elements to engage.